What is a Router?
A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Routers maintain information about what networks they are connected to and can translate between different types of networks. Traffic that is destined for a network that your router doesn’t sit in front of is sent to the next hop upstream. From there, traffic destined for remote networks passes from router to router along its path until it reaches its destination. This is the basic concept that makes the entire Internet work!
A router is connected to two or more data lines from different networks. When a data packet comes in on one of the lines, the router reads the network address information in the packet to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey.
Large enterprises often have layers of routers inside their networks, with distribution routers handling traffic between geographically connected network segments, core routers handling traffic from distribution routers, and border routers sending traffic offsite to other parts of the corporate network and the Internet.
When multiple routers are used in interconnected networks, the routers can exchange information about destination addresses using a routing protocol. Each router builds up a routing table listing the preferred routes between any two systems on the interconnected networks.
A router may have interfaces for different types physical layer connections, such as copper cables, fiber optic, or wireless transmission. Its can also support different network layer transmission standards. Each network interface is used to enable data packets to be forwarded from one transmission system to another. Routers may also be used to connect two or more logical groups of computer devices known as subnets, each with a different network prefix.
Routers may provide connectivity within enterprises, between enterprises and the Internet, or between internet service provider (ISPs) networks.
In addition to their traffic routing capabilities, routers can provide a number of security related functions, including the following:
- Access control lists (ACLs) Rules that provide basic packet filter capabilities.
- Quality of service (QoS) Prioritization of queues of packets and traffic, allowing higher-priority traffic to be handled first for protocols like Voice over IP (VoIP), where real-time responses are important.
- Denial of service (DoS) attack prevention Some routers have protections built in to help avoid or prevent denial of service attacks on the networks they protect.
There are routers of all sizes available on the market, from simple home routers that your Internet service provider provides or that you purchase, to giant enterprise-class routers that cost hundreds of thousands of dollars. Enterprise routers often have the ability to add redundant capabilities like extra power supplies, backup control modules, and even entire firewalls and other major devices in a single box.
What to Consider When Buying a Wireless Router
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